Most Finnish anti-aircraft guns were deployed around the cities to protect them from Soviet air raids, but a few 20mm and 40mm weapons protected the troops on the front line.

Thirty German 20mm ItK/30 (FlaK38) guns were delivered just before the Winter War and another 20 arrived in early December 1939. The Finns also had 53 40mm ItK/38 (Bofors) at the outbreak of the Winter War.